cheap A/D Converter (was Re: Occilliscope)

[Andrew W. Macfadyen]

I used the ADC0804 on mine worked pretty well, working through a hex buffer
(74LS244)   to enable the reading of 8 data bits through 4 input bits (on pins
10,12,13 and 15 on the printer port), a hex inverter (74LS04) connected to pin
1 of the  printer port to toggle the  handshake line to the inverter.
I then added a op-amp input stage (AD622N) for signal conditioning and a an
analogue switch to give software selectable inputs.
I used a compiled basic for the very crude software but I am trying the
sharware "Euphoria" language for a MK2 version..

Roger Heflin wrote:

> On Wed, 29 Jul 1998, Jason Weir wrote:
>
> > Roger Heflin wrote:
> >
> > > If you want to do some electronics and a computer, you can get a cheap
> > >
> > > A/D convertor (ADC820 I believe), and wire it into the paralell port.
> > > You can do it without any extra circuitry except an external power
> > > supply to power the A/D.  The convertor is good for 600khz (good
> > > enough for auto use) and with a PC paralell port (on a 486 or so) you
> > > can get at least 20 khz or so out of it with quick basic.  If you
> > > use something more serious (C or Assembler) you can get closer to
> > > 100khz out if it.
> >
> > Not sure if this is what your talking about but its a simple A/D
> > converter using the parallel port, check it out, probably cost about $10
> > at radio shack...I was interested in using it to log O2, TPS, VSS and
> > some other things but never got around to trying it yet, let me know
> > how, if anything turns out,  Jason
> >
> > http://www.repairfaq.org/filipg/LINK/F_AD4PC.html
> >
> >
>
> Same idea, different convertor and different wiring than I did on the one
> I had.  I have only breadboarded, I have not finished wirewrapping the
> more durable circuit.
>
>                         Roger